The influence of environmental effects on excited-state lifetimes. The effect of ion pairing on metal-to-ligand charge transfer excited states

1985 ◽  
Vol 89 (7) ◽  
pp. 1095-1099 ◽  
Author(s):  
William J. Vining ◽  
Jonathan V. Caspar ◽  
Thomas J. Meyer
Keyword(s):  
Excited State ◽  
Charge Transfer ◽  
Excited States ◽  
Environmental Effects ◽  
Ion Pairing ◽  
Ligand Charge Transfer ◽  
Excited State Lifetimes

A density functional theory and spectroscopic study of intramolecular quenching of metal-to-ligand charge-transfer excited states in some mono-bipyridine ruthenium(II) complexes

2014 ◽  
Vol 92 (10) ◽  
pp. 996-1009 ◽  
Author(s):  
Shivnath Mazumder ◽  
Ryan A. Thomas ◽  
Richard L. Lord ◽  
H. Bernhard Schlegel ◽  
John F. Endicott
Keyword(s):  
Density Functional Theory ◽  
Excited State ◽  
Charge Transfer ◽  
Excited States ◽  
Lower Energy ◽  
Density Functional ◽  
Dimethyl Sulfide ◽  
Intramolecular Electron Transfer ◽  
Functional Theory ◽  
Ligand Charge Transfer

The complexes [Ru(NCCH3)4bpy]2+ and [Ru([14]aneS4)bpy]2+ ([14]aneS4 = 1,4,8,11-tetrathiacyclotetradecane, bpy = 2,2′-bipyridine) have similar absorption and emission spectra but the 77 K metal-to-ligand charge-transfer (MLCT) excited state emission lifetime of the latter is less than 0.3% that of the former. Density functional theory modeling of the lowest energy triplet excited states indicates that triplet metal centered (3MC) excited states are about 3500 cm−1 lower in energy than their 3MLCT excited states in both complexes. The differences in excited state lifetimes arise from a much larger coordination sphere distortion for [Ru(NCCH3)4bpy]2+ and the associated larger reorganizational barrier for intramolecular electron transfer. The smaller ruthenium ligand distortions of the [Ru([14]aneS4)bpy]2+ complex are apparently a consequence of stereochemical constraints imposed by the macrocyclic [14]aneS4 ligand, and the 3MC excited state calculated for the unconstrained [Ru(S(CH3)2)4bpy]2+ complex (S(CH3)2 = dimethyl sulfide) is distorted in a manner similar to that of [Ru(NCCH3)4bpy]2+. Despite the lower energy calculated for its 3MC than 3MLCT excited state, [Ru(NCCH3)4bpy]2+ emits strongly in 77 K glasses with an emission quantum yield of 0.47. The emission is biphasic with about a 1 μs lifetime for its dominant (86%) emission component. The 405 nm excitation used in these studies results in a significant amount of photodecomposition in the 77 K glasses. This is a temperature-dependent biphotonic process that most likely involves the bipyridine-radical anionic moiety of the 3MLCT excited state. A smaller than expected value found for the radiative rate constant is consistent with a lower energy 3MC than 3MLCT state.

Picosecond to Nanosecond Manipulation of Excited-State Lifetimes in Complexes with an FeII to TiIV Metal-to-Metal Charge Transfer: The Role of Ferrocene Centered Excited States

2019 ◽  
Vol 58 (22) ◽  
pp. 15320-15329 ◽  
Author(s):  
Maksim Y. Livshits ◽  
Michael D. Turlington ◽  
Carl O. Trindle ◽  
Lei Wang ◽  
Zikri Altun ◽  
...  
Keyword(s):  
Excited State ◽  
Charge Transfer ◽  
Excited States ◽  
Metal Charge ◽  
Excited State Lifetimes ◽  
Metal Charge Transfer

scholarly journals Solvatochromic and Ligand Effects in Ultrafast Intramolecular Electron Transfer in Fe-based Molecular Photosensitizers

2019 ◽  
Vol 205 ◽  
pp. 09029
Author(s):  
Kristjan Kunnus ◽  
Lin Li ◽  
Marco Reinhard ◽  
Sergey Koroidov ◽  
Kasper S. Kjaer ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Excited State ◽  
Charge Transfer ◽  
Driving Force ◽  
Reorganization Energy ◽  
The Other ◽  
Intramolecular Electron Transfer ◽  
Ligand Effects ◽  
Ligand Charge Transfer ◽  
Excited State Lifetimes

Metal-to-ligand charge-transfer (MLCT) excited state lifetimes of [Fe(CN)4(2,2’-bipyridine)]2- and [Fe(CN)4(2,3-bis(2-pyridyl)pyrazine)]2-exhibit strong solvent and ligand dependence. We conclude that these effects can be described with Marcus-like model where changes in the MLCT energy correspond directly to the changes in the electron transfer driving force and all the other factors (e.g. reorganization energy) can be considered constant.

Tuning of the lowest excited states in mixed ruthenium(ii) polypyridyl complexes having RuN6 cores by the conformation of the ancillary ligand. Emission from a 3ligand-to-ligand-charge-transfer state

2016 ◽  
Vol 40 (6) ◽  
pp. 5002-5009 ◽  
Author(s):  
Nirmal K. Shee ◽  
Michael G. B. Drew ◽  
Dipankar Datta
Keyword(s):  
Excited State ◽  
Charge Transfer ◽  
Excited States ◽  
Small Difference ◽  
Charge Transfer State ◽  
Ancillary Ligand ◽  
Polypyridyl Complexes ◽  
Ligand Charge Transfer ◽  
Transfer State

A small difference in the conformation of an ancillary ligand L determines the lowest excited state in [Ru(bpy)2L]2+ and [Ru(phen)2L]2+.

Synthesis and Photochemical Properties of Re(I) Tricarbonyl Complexes Bound to Thione and Thiazole-2-ylidene Ligands

2020 ◽  
Author(s):  
Matthew Stout ◽  
Brian Skelton ◽  
Alexandre N. Sobolev ◽  
Paolo Raiteri ◽  
Massimiliano Massi ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Excited States ◽  
Ligand Exchange ◽  
Ligand Substitution ◽  
Bidentate Ligand ◽  
The Other ◽  
Ligand Exchange Reaction ◽  
Multiple Products ◽  
Ligand Charge Transfer ◽  
Photochemical Properties

<p>Three Re(I) tricarbonyl complexes, with general formulation Re(N^L)(CO)<sub>3</sub>X (where N^L is a bidentate ligand containing a pyridine functionalized in the position 2 with a thione or a thiazol-2-ylidene group and X is either chloro or bromo) were synthesized and their reactivity explored in terms of solvent-dependent ligand substitution, both in the ground and excited states. When dissolved in acetonitrile, the complexes bound to the thione ligand underwent ligand exchange with the solvent resulting in the formation of Re(NCMe)<sub>2</sub>(CO)<sub>3</sub>X. The exchange was found to be reversible, and the starting complex was reformed upon removal of the solvent. On the other hand, the complexes appeared inert in dichloromethane or acetone. Conversely, the complex bound to the thiazole-2-ylidene ligand did not display any ligand exchange reaction in the dark, but underwent photoactivated ligand substitution when excited to its lowest metal-to-ligand charge transfer manifold. Photolysis of this complex in acetonitrile generated multiple products, including Re(I) tricarbonyl and dicarbonyl solvato-complexes as well as free thiazole-2-ylidene ligand.</p>

Molecular and electronic structure in the metal-to-ligand charge-transfer excited states of d6 transition-metal complexes in solution

1984 ◽  
Vol 106 (12) ◽  
pp. 3492-3500 ◽  
Author(s):  
Jonathan V. Caspar ◽  
T. David Westmoreland ◽  
George H. Allen ◽  
Paul G. Bradley ◽  
Thomas J. Meyer ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Charge Transfer ◽  
Transition Metal ◽  
Metal Complexes ◽  
Excited States ◽  
Transition Metal Complexes ◽  
Ligand Charge Transfer ◽  
Molecular And Electronic Structure

Subpicosecond Dynamics of Metal-to-Ligand Charge-Transfer Excited States in Solvated [Ru(bpy)3]2+ Complexes

2011 ◽  
Vol 115 (31) ◽  
pp. 15617-15626 ◽  
Author(s):  
Diego A. Hoff ◽  
Robson Silva ◽  
Luis G. C. Rego
Keyword(s):  
Charge Transfer ◽  
Excited States ◽  
Ligand Charge Transfer
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